Aircraft landing gear often have shock-absorbing dampers used in landing and ground operations. Conventional dampers typically use a fixed viscosity fluid that, during compression or extension, is forced through an orifice of fixed or variable size. Landing gear often absorb significant amounts of energy during landings, yet also provide firm ground handling during lower speed operations, such as taxiing. Often, however, a shock-absorbing damper that provides firm ground handling at lower speed operations is not ideal for absorbing significant energy during landings, and vice-a-versa.
The ability to control energy dissipation rates depending on loading conditions has been an active area of research over the past few decades. One of the more studied areas involves using a fluid that has a viscosity that is variable in response to a controlled magnetic field (magnetorheological fluids) or a controlled electric field (electrorheological fluids). Such fluids have shear thickening performance but are limited due to the particle size and because their use is associated with equipment for generating and sustaining electric and/or magnetic fields.